Panoramic imaging systems are common in a variety of applications including medical endoscopy, surveillance, bore hole inspection, and pipe inspection. Panoramic imaging allows for a full radial view of the surroundings usually from a single point. In the example of pipe inspection, the integrity of the interior pipe wall can be inspected by feeding an imaging system down the center of the pipe to view the interior wall. Panoramic imaging can be achieved in a variety of ways as established by the details of the prior art described below.
U.S. Pat. Nos. 5,652,617 and 4,855,820 disclose bore hole video inspection systems that comprising two completely independent imaging systems, one for forward viewing and the other for side viewing. The forward-viewing imaging system comprises a forward-facing video camera with a wide angle lens. The side viewing imaging system comprises a forward facing video camera with a gyroscopically controlled angular mirror and lens system for viewing 50 degree segments of the side view with the camera. The gyroscope rotates to collect the entire 360 degree radial image.
The primary applications for panoramic imaging systems such as these is the inspection of pipelines, tubing or bore holes. There are many important aspects of obtaining reliable and useful imaging data. Ease of tracking and identifying imaging locations is a critical factor in using the acquired images to repair damaged areas. Imaging systems that sweep the view and acquire multiple images throughout the entire 360 degree sweep have several disadvantages. For example, in tight remote spaces, moving parts are difficult to control and are also subjected to repeated wear leading to eventual failure. Multiple images require reconstruction in image post-processing to create the full 360 degree view. Overlap of image fields wastes storage capacity, but without it risks are taken in missing critical views and important information. And location tracking in these systems is often difficult.